Figure 3. Expression of Tmtc4 and its isoforms in mice.

In heterozygous Tmtc4-KO mice, β-gal expression is driven in the KO allele by the Tmtc4 promoter. β-gal expression is seen broadly in the cochlea, particularly in the stria vascularis (SV), spiral ligament (SLg), and organ of Corti (OC), with less expression noted in the spiral limbus (SLm) and spiral ganglion (SG). (B) In a magnified view of A, the organ of Corti contains inner (IHC) and outer (OHC) hair cells, as well as supporting cells (pillar cells [PC], Dieter’s cells [DC], and Claudius cells [CC]), with robust labelling. (C) WT control mice, in which Tmtc4 promoter–driven β-gal expression is not present, shows no β-gal antibody labeling, demonstrating that the broad labelling seen in A and B is specific.